[x3d-public] Philosophical contemplations

[Joe D Williams]

X3D is really nD+1
where n is the number of dimensions needed for the show, plus the 
observer's interface.
Joe

----- Original Message ----- 
From: "Roy Walmsley" <roy.walmsley at ntlworld.com>
To: <x3d-public at web3d.org>
Sent: Tuesday, December 06, 2016 5:39 AM
Subject: Re: [x3d-public] Philosophical contemplations


> Hi again,
>
>
>
> I had some personal replies as follows:
>
>
>
> Imperative includes verbs.   Declarative does not????
>
> Or, declarative is who what where when and imperative is how.
>
> And why is causative. X5D?
>
>
>
> A question then: Is X3D, in its current form, declarative or 
> imperative?
>
>
>
> For example, I might have the following simple scene extract:
>
>
>
> <Group>
>
>  <Transform translation = "0,0,2">
>
>    <Shape>
>
>      <Box>
>
>      </Box>
>
>    </Shape>
>
>  </Transform>
>
> </Group>
>
>
>
> Is this declarative, or imperative? I've simply told it to draw a 
> box, in
> the specified location, with the default size and appearance. I 
> haven't told
> it how to draw the box. On the other hand, I didn't say "Draw a box 
> with its
> centre two metres off the ground.". Neither did I say "Draw a 
> scene".
> Granted, there are no verbs. There again, X3D doesn't have them! In
> comparison, however, I have told it how to draw a scene.
>
>
>
> It's all a matter of the level of abstraction that you're basing 
> your
> judgement on. And whether you are looking up or down .
>
>
>
> Roy
>
>
>
> From: x3d-public [mailto:x3d-public-bounces at web3d.org] On Behalf Of 
> Roy
> Walmsley
> Sent: 06 December 2016 12:00
> To: x3d-public at web3d.org
> Subject: [x3d-public] Philosophical contemplations
>
>
>
> Hi,
>
>
>
> First, a disclaimer. The contemplations below do not claim to 
> represent the
> viewpoint of the Web3D Consortium. Indeed, they may not even 
> represent my
> own personal viewpoint. They are expressed purely as stimulation for
> discussion.
>
>
>
> ----------------------------------------------------------------------------
> ----------------------------------------------------------------------------
> ---------------------------------------------------------------------------
>
>
>
> Contemplation 1
>
>
>
> Recently Leonard has been seeking comments about "Essential elements 
> of
> X3D". While I would suggest that the question is not well phrased, 
> since he
> is probably thinking about what should be in the next version of 
> X3D, it did
> lead me into thinking more liberally.
>
>
>
> X3D
>
> X3D - Extensible 3D.
>
>
>
> Imagine sitting in your own office or living room. Contemplate what 
> X3D
> structures (nodes) you would want available to model it. Pause for 
> thought .
>
>
>
> Now, consider what structures (nodes) you would want to build a
> representation of the real thing, as opposed to the virtual one. 
> Pause for
> thought .
>
>
>
> Now, extend that last thought to consider what structures (nodes) 
> you would
> want to build a representation of the whole building. Pause for 
> thought .
>
>
>
> And why stop there, what about the whole town (or city, or village, 
> as
> appropriate), or the whole country, or the whole earth, or the whole 
> solar
> system, or even the universe. Long pause for thought (and ignore any
> practicalities such as data size) .
>
>
>
> But why just 3D? These places aren't static. They are dynamic. A 
> fourth
> dimension, time, is involved. It took time for me to write this 
> e-mail. It
> will take you time to read it (or maybe tl:dr).
>
>
>
> What structures (nodes) are required to fully  support this extra 
> dimension?
> At any or all of these levels. Pause for thought .
>
>
>
> So should we, perhaps, be calling this extensible 4D? I.e.
>
>
>
> X4D
>
> Coincidentally, the next version of X3D is planned to be version 4 
> !!
>
>
>
> ----------------------------------------------------------------------------
> ----------------------------------------------------------------------------
> ---------------------------------------------------------------------------
>
>
>
> Contemplation 2
>
>
>
> Imperative, or declarative. There's no such thing! What they really 
> are is
> levels of abstraction.
>
>
>
> Let's take, as an illustration, humanoid animation. Assume we have 
> built an
> H-Anim figure, fully skinned, and clothed (or, to use other 
> terminology, we
> have taken our mesh model of a humanoid and fully rigged it ready 
> for
> animation). Now we can define a simple "step left foot forward" 
> motion, by
> specifying a few joint rotations. Is this declarative or imperative
> programming? All the details about vertex transformations are hidden 
> from
> the animator by the H-Anim implementation.
>
>
>
> Similarly, we can define "step right foot forward", "swing left 
> arm", "swing
> right arm", "look left", "look ahead", etc, etc.
>
>
>
> Now, consider the requirements for defining "walk from Point A to 
> Point B".
> We could define it in terms of the basic motions referred to above. 
> Is this
> declarative or imperative programming?
>
>
>
> Similarly, we could define "get in the car", "drive from Point C to 
> Point
> D".
>
>
>
> We can then consider generalising it some more, to define the motion 
> "go to
> work". This might involve the sub-steps "Leave the house", "walk to 
> the
> car", "get in the car", "drive to the work car park", "get out of 
> the car",
> "walk from the car park to the office". Each of these steps is 
> broken down
> more. So "walk to the car" involves, at the very least, "step left 
> foot
> forward", "step right foot forward" multiple times (no comments 
> about
> hopping please!). Each single step motion involves individual joint
> rotations, which in turn are used to calculate vertex 
> transformations. To
> say nothing of rendering the model at each frame from the start to 
> the
> finish.
>
>
>
> So, it's really about choosing the abstraction levels. Optimising 
> each one,
> and allowing appropriate parameterisation .
>
>
>
> ----------------------------------------------------------------------------
> ----------------------------------------------------------------------------
> ---------------------------------------------------------------------------
>
>
>
> Well, that's enough for now,
>
>
>
> Feel free to come up with your own .
>
>
>
> Roy
>
>
>
>


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